Strength enhancement of nanostructured organogels through inclusion of phthalocyanine-containing complementary organogelator structures and in situ cross-linking by click chemistry

Stable photoactive organogels were successfully prepared by a two-step sequence involving: 1) formation of thermoreversible organogels by use of a combination of low-molecular-weight organogelators (LMOGs) and ZnII-phthalocyanine (ZnII-Pc) moieties containing complementary organogelator structures, and 2) strength enhancement of the gels by in situ cross-linking with the aid of CuI-catalysed azide-alkyne [3+2] cycloadditions (CuAACs). The optimum click reaction was carried out between a flexible C6 aliphatic diazide and a suitable dialkyne (molar ratio 1:1) added in a low proportion relative to the organogelator system [LMOG+ZnIIPc]. The dialkyne unit was incorporated into a molecule resembling the LMOGs structure in such a way that it could also participate in the self-assembly of [LMOG+ZnIIPc]. The significant compatibility of the multicomponent photoactive organogels towards this strengthening through CuAACs allowed their sol-to-gel transition temperatures (Tgel) to be enhanced by up to 15 degrees C. The Tgel values estimated by the "inverse flow method" were in good agreement with the values obtained by differential scanning calorimetry (DSC). Rheological measurements confirmed the viscoelastic, rigid, and brittle natures of all Pc-containing gels. Transmission and scanning electron microscopy (TEM, SEM) and atomic force microscopy (AFM) revealed the fibrilar nature of the gels and the morphological changes upon cross-linking by CuAAC. Emission of a red luminescence from the dry nanoscale fibrous structure-due to the self-assembly of the Pc-containing compounds in the organogel fibres-was directly observed by confocal laser scanning microscopy (CLSM). The optical properties were studied by UV/Vis and fluorescence spectroscopy. Fluorescence, Fourier-transform infrared (FTIR) and circular dichroism (CD) measurements were also carried out to complete the physicochemical characterization of selected gels. As a proof of concept, two different organogelators (cholesterol- and diamide-based LMOGs) were successfully used to validate the general strategy.     

透明质酸纳米材料在荧光/光声成像和光疗中的应用

荧光/光声成像和光疗技术的生物医学应用引起了人们越来越多的关注, 然而很多荧光/光声造影剂存在生物相容性较差, 缺乏肿瘤靶向性, 信噪比较低, 功能单一等共性问题, 严重限制其诊疗应用. 透明质酸具有优异的生物相容性和主动肿瘤靶向性, 可被透明质酸酶降解, 并且易于化学修饰和实现多种超分子弱相互作用力协同工作. 因此, 人们将透明质酸与荧光/光声造影剂结合制备纳米材料, 使其在细胞乃至活体的标记性能和治疗效果获得了很大的改善. 本文综述了将两类物质结合制备纳米材料的方法, 着重阐述了纳米材料的结构与性能关系, 为其未来设计和开发提供了指导, 最后对存在的主要问题以及未来的重要研究方向进行了分析和展望.     

聚合物纳米光诊疗剂的制备与应用新进展

共轭聚合物纳米颗粒是由π-共轭有机聚合物组成的尺寸在1~100nm范围内的新型有机纳米材料。与传统的有机小分子、半导体量子点和无机纳米材料相比,聚合物纳米颗粒具有光学性质特殊、结构多样、表面易修饰和生物相容性好等优点,因而被广泛应用于生物成像、传感与检测、载药和治疗等领域。本文主要围绕聚合物纳米颗粒的制备方法、性质结构和生物相容性等方面,重点介绍了聚合物纳米颗粒作为光诊疗剂在荧光成像、光声成像,以及光动力和光热治疗领域的研究进展,并对聚合物纳米颗粒的发展前景和未来面临的挑战进行了探讨。     

肿瘤靶向Pt-Cu基纳米平台用于近红外二区光声成像引导的光热治疗

基于层层（LBL）自组装技术,在Pt-Cu纳米合金表面依次包覆带正电的聚赖氨酸（PLL）和带负电的透明质酸（HA）,成功构筑Pt-Cu@PLL@HA纳米平台。HA不仅延长了纳米平台血液循环时间,还可实现肿瘤主动靶向作用,提升肿瘤部位富集效果。在肿瘤区域透明质酸酶（HAase）作用下HA快速降解,释放Pt-Cu@PLL （+）颗粒,有利于肿瘤细胞特异性摄取。基于Pt-Cu合金良好的近红外二区（NIR-Ⅱ）吸收性能,实现了NIR-Ⅱ光声成像引导的NIR-Ⅱ光热高效抗肿瘤效果。     

Chemical Imaging of Monolayers on Metal Surfaces: Applications in Corrosion,Catalysis, and Self‐Assembled Monolayers

In situ techniques are indispensable to understanding many topics in surface chemistry. As a consequence, several spectroscopic methods have been developed to provide molecular‐level information that only spectroscopy can supply. However, as important as this information is, it is just as critical to realize that nearly all surfaces under investigation have spatial heterogeneities of the order of nanometers to millimeters; thus, spatial analysis is very important to the overall interpretation. This Minireview focuses on a few of the recent developments in spectroscopic techniques that can provide spatial, spectroscopic, and in situ information. These techniques include photo‐electron microscopy, infrared and Raman imaging, and nonlinear optical imaging vibrational spectroscopy as applied to topics in corrosion, catalysis and self‐assembled monolayers.     

Novel phthalocyaninatobis(alkylcarboxylato)silicon(IV) compounds: NMR data and X-ray structures to study the spacing provided by long hydrocarbon tails that enhance their solubility

The reaction between trans-PcSiCl2 (1) and the potassium salts of six fatty acids (2 a-2 f) led to the trans-PcSi[OOC(CH2)nCH3]2 compounds (3 a-3 f), which were characterised by elemental analysis, IR, UV/Vis and 1H, 13C, and 29Si NMR spectroscopy. From a detailed study of the NMR spectra, the strong anisotropic currents of the Pc macrocycle were found to have an effect on up to the sixth methylenic group. As expected, the length of the hydrocarbon tail does not affect the chemical shift of the 29Si nucleus of any of the compounds, appearing at around -222.6. The structures of PcSi[OOC(CH2)nCH3]2, where n = 7, 10, 12, 13 and 20, were determined by X-ray crystallography. All the compounds were found to be triclinic with a P1 space group. In all cases the observed crystallographic pseudosymmetry is Ci and the asymmetric unit consists of half a molecule. The silicon atom is at the centre of a distorted octahedron and hence its coordination number is six. The carboxylate fragments are in a trans configuration with respect to the Pc macrocycle. The supramolecular structures are discussed in detail herein. The correlation between the 1H NMR chemical shifts and the position of the corresponding carbon atoms in the hydrocarbon tail reveals that the dicarboxylate substituents exhibit a spacer-like behaviour that enhances the solubility. A detailed study of the tail variable allowed us to evaluate the loss of radial shielding along the Pc2- ligand.     

Fiber array based hyperspectral Raman imaging for chemical selective analysis of malaria-infected red blood cells

A new setup for Raman spectroscopic wide-field imaging is presented. It combines the advantages of a fiber array based spectral translator with a tailor-made laser illumination system for high-quality Raman chemical imaging of sensitive biological samples.     

Raman Spectroscopic Imaging for the Real‐Time Detection of Chemical Changes Associated with Docetaxel Exposure

There is an urgent need for methods allowing for a fast, non‐invasive, sensitive and selective monitoring of the effectiveness of anticancer drugs during the course of a chemotherapeutic treatment of cancer patients. The possibility of predicting and controlling the efficiency of chemotherapeutic agents for every patient individually enables a personalized therapy with largely improved success rates. The results presented herein demonstrate that Raman microspectroscopy is perfectly suited to monitor the impact of chemotherapeutic agents on living cells. The influence of the clinically well‐established chemotherapeutic docetaxel on both the morphology and also biochemistry of living colon cancer cells (HT‐29) has been studied by means of Raman spectroscopy in combination with modern chemometric approaches. The work presented paves the way for establishing Raman spectroscopy as a monitoring tool of the effectiveness of a chemotherapy treatment and can therefore be seen as a step towards personalized therapy.